Evaporator



Feb. 12, 1946.

o. J. KuENHoLD EVAPORATOR4 3 Sheets-Sheet 1 5 lNvENTR. BY Orro JIKuENHoLD, SR.

Original Filed OG'(H 6, 1958 ATTORNEYS.

Feb. 12,1946.

o. J. KUENHLD, SR

EVAPORATOR Original Filed Oct. 6, 1938 3 Sheets-Sheet 2 INVENTOR. OrroJ2 KUENHOLD, Se.

ATTORNEYS.

Feb. 12, 1946.

O. J. KUENHOLD, SR

EvAPoRAToR 3 Sheets-Sheet 3 Original Filed Oct. 6, 1938 INVENTOR. OrroJ.' KuENHoLQR.

BY @www4 ATTORNEY Patented Feb. 12, 1946 UN IT ED STAT E S PAT 0F Fl CEv EvAioRA'roR Otto J. Kuenhol'd, Sr., Shaker'Heights,: Ohio, assgnor toMonmouth Productsompany, Cleveland, Ohio', a corporation of (Jho dContinuation of application Serial No'. 340,827, June 1940, which is adivis-ol'i'ff- Serial No.

233,631, October 6, 1938.A

August 7, 1942, seal No'. 453,990

11 claims'.

The present invention relatesy to an evaporatin'g device particularlyadapted for use in the heating, Ventilating and air conditioning art,and is of the type wherein evaporation of water and its entrainment in apassing air stream is obtained by means of porous, ceramic plates dismyUnited states Letters Patent No. 2,166,414,-

granted July 18, 1939, for Humidifying system. The present applicationis a continuation of my divisional application Serial Number 3&'O,82'7,ile'd June 15, 1940, said divisional application being a division of myapplication Serial Number 233,631, filed October 6', 1938, and issuedApri-l 1v,- 1941,` as United States letters Patent No. 2,236,538.

The general object and nature of my present invention vis to provide anevaporator of the type indicated having a much greater evaporation ratecapacity and increased life or period of service. Additional objects andadvantages of the invention shall become apparent as the follov'vir'igVdescription proceeds.

To the accomplishment of the foregoing and related ends, said invention,then, consists of the means hereinafter fully described and particularlypointed out in the claims. v The annexed drawings and the' followingdescription setforth in detail certair'iI mechanism embodying theinvention, such disclosed means constituting, however, but one ofvarious Inechanical forms in which the principle of the invention may beused.

In said annexed drawingshand endg elevation f the: water Dan; Fig. 11 isa cross-"setional view taken substantially along the line l'l-r-'ill{if} 7; Fig'. 12y is a longitudinal sectional view' showing one' meansof varying the Fig. 1 is a view illustrating an evaporating' plate ofFig. 1; Fig. 3 is a partially diagrammatic figure ofan evaporator plateand water pan and is for the purpose of aiding in the explanation of theprinciple of my invention; Fig. 4 is a top plan view of onefhalf of oneof the evaporating plates having the improved construction; Fig. 5 is alongitudinal sectional view of the water pan and 'supporting' rackwitli'one of the evapo'rating plates shown in positionj Fig. 6 is a topplan view of the evaporator embodying the principle of my invention;Fig. 7 is a side elevational view thereof; Fig. 8 is a cross-sectionalview taken substantially along the line 8.-'8 of Fig. 7i Fig. 9 is anend elevational viewof the cover plate and water `feed apparatus for theevaporator; Fig. 1U is a right height oi the evaper'eting plates withrespect to the Wafer level;- rid' Fig. lf3 is a longitudinal sectionalview'shovving an alternative means of vary'- ing the height of the'evaporatingv plates with respeol" t0 the Watrl'evel.

Now referring to Figs. 1 and 2, it will be seen that the' porousceramic' evaporating plate I shownthereii is in the form of a rectanglewith a central downwardly extending tongue 2 c'ontacting withtl'e waterin the Water pan or reservoirl 3. Projections 4' are provided in thebottoni f the' for' engaging withV the tongue 2 and notches 5 are videdin the upper edges of., the pan 3 for engaging with the body portion of.the plate l. yThe above illustrated and de"- scribed onst'ruc'tion isfurther set uforth and claimed in; my aforesaid Patent No.y 2,166,414. K

Porous, ceramic evaporating plates operate generally upon the principle'of absorbing water from the W'atby capillary action, presenting4exposedvwet or' moistend surfaces for contact with a passing airstreairi.l

New referring to Fig. 3, there is shown therein an evaporating plateconsisting generally of the two half portions and B. A series of dottedline curves a to h inclusive represent the upper limits of Vth wet vormoistened area of the Plate at the following timeintervals' after the dlY Plate has been inserted in the Water pan with the level maintained atthe line marked WL, viz.:

Upper limit of water penetrationV These curves a to h inclusiverepresent a careful copy of pencil linesi'nade on the face of the plateduring actual test. Curve g 'correspondingl therefrom and presents anabutting edge adapted to bear against the bottom of the slots of therack 2|. The latter is laid upon the bottom of the water pan 20 and isalso of inverted V-shaped cross-section with the upwardly-extendingqmarginal edges 22 which also contact with thebottom edges ofthe tongue portion I5 of the evaporating plate B. Transverse slots 23are provided at intervals in the rack 2| for spacing the plates B.

I have made the discovery that if the plate is of cumulating and cuttingdown the pore area until water can no longer pass through the innerpores of the plates as fast as the plates can evaporate it.

A third type of clogging action occurs but. this occurs either in platesnot having correct outline or when plates considerably clogged bycalcium and magnesium carbonates as described in the preceding paragraphare continued in service. In

' either one of these two cases, the outermost areas of the plates, lastto receive the water, become dry. Evaporation then occurs from theinnermost areas of the plates, these areas being bounded respec- Ytively by lines defined by mineral salts which are taperedcross-section, thicker at the bottom than edges at top andsides,asindicated by top view Fig. 4, the capillary advance of the waterlaterally would be more rapid and the curves a to h inclusive Wouldextend out furtherv laterally. y This means that the plate can beextended laterally substantially as sho-wn `at I2, I3 and III, and stillremain as wet in service at the extreme lateral edges as it does `in therectangular lform of Figs.

1 and 2. In other Words, moreevaporation could be secured per platewithout danger of the outer `edges remaining. insufficiently moistforeicient vevaporating service and durability. The tapering Yof the plateas described not only adds'to the l eflicient evaporation per plate butextends its period of eiiicient service as'will be mode fully explainedlater.V f

All city supplied water contains dissolvedmineral salts and floatingmatter such as algae and -ircn oxidesv (rust). All city supplied waterpasses through iron pipes and the rust so formed by'action of the waterand its Ycontents upon the inner walls of the iron mains and pipes. Thefloating matter in the water enters and clogs the inlet pores of theplates. Y 1 Any mineral salts dissolved in the water freely enters theinlet pores and is carriedV by the capillaryl iiowoutward toward theouteredges of the plates. The water itself is evaporated from thelsurfaces of the plates but the soluble salts accumulate on the outeredges of the plates. As the rapid water evaporation from the surfaces ofthe platesreduces their temperature, the mineral accumulations on theouter edges of the plates remains soft, porous, moist and easily brushedofi from time to time-each year or two normally.l

Besides the mineral salts which remain permalnently soluble as abovedescribed, city supplied water also contains calcium and magnesiumcarbonates which remain dissolved in the water if the water alsocontains carbon dioxide, as is almost invariably'the case. But an actiontakes place vwhich seems to be as follows: When the water enters the panwhere it is warmed somewhat by the warm air circulating around and pastthe pan and plates, the carbon dioxide begins to escape and continues todoso after the water enters the plates. The calcium and magnesiumcarbonates can then kno longer be heldin solution by the plates,especially near the inlet end, gradually acdeposited along these linesand block the iiow of Ywater past these lines within the plates.

To prevent the first named ltype of clogging',l that is clogging of theinlet pores of the plate by floating matter in the supplied Water, Ihavev found it practically imperative to provide a water` filtercontaining a filter medium composed of the same porous material as theplates. Such a filter medium can be conveniently installed in either ofthe feed lines 36 or 31. This filtering medium thus passes floatingmatter that will not clog the inlet pores of the plates but stopsfloating matter thatl would clog the inlet pores of the plates. Thefilter is then cleaned from time to time which is very much easier to dothan to remove and clean all the plates. s

There will then still remain in the water floating oxides formed byYaction of the Water upon the inner wall of the metal tubing from thelter to the water pan. This too would clog ther inlet pores of the platewithin possiblyv a couple months but to extend this time limit to a fullseason or two, I provide much greater inlet area such as indicated atI5, than is actually necessary. In this way I am able to extend theactive efcient service period of the inlety surface upto a time wheninternal plate clogging makes attention to vthe 'preceding paragraph andalso by the tapern ing of the plate, making .it thicker toward the inletarea, as has been described, this tapering adds considerable to theactive service vperiod of theV plate before internal cloggingaccumulates to the point Where evaporation is impaired, The more rapidand therefore more effective capillary flow induced by the taperingformation also helps 4to extend the active life of the plate for otherbut not yet known reasons.

In addition to the steps taken asabove described two other steps aretaken to cope with internal deposits. I have found that certain sol-Events and acids suchV as hydrochloric acid readily then be washed outwith water substantially as if the deposits were sugar. I therefore makethe plates of a material which is unaifectedby hydrochloric acid andother calcium or magnesium carbonate solvents. In addition I maketheplates of a material having rather coarse capillarity Vto facilitatethe washing out process and at the same time provide ample voids foraccumulation of inservice period is attained.

ternal deposits so that longest Vpossibleactive I have furthermorediscovered thatif, while the plates are in servicey a solvent such asacetic water, consequently they are deposited in the acid or`hydrochloric acid in relatively small and harmless quantity isadded tothe water in the ban from time to time, it converts insoluble aceVcumulations in the plates to soluble salts and the capillary iiow withinthe plates thereupon carries the said accumulations, then in solubleform, to the surface and toward the outer edges of the plates. y

Figs. 6 and 11 illustrate the evaporator as assembled in a heatingfurnace bonnet or plenum chamber. The guides 25 on the sides o'f the pan22 engage with the 'support rods 2li which ex'- tend through to theouter wall 2`| of the furnace. A hook bolt 28 connects the inner orright hand end of the pan 20 to the ceiling or top wall 29 of thefurnace and is attached by means 'of the nut 3|). As shown in Fig. 10,an extension Strip '23 may be used in the event that the hook bolt isnot of sufcient length. Openings 3| and 342 are provided in the innerand outer furnace lwalls 2l and 21' respectively for access to theevaporator pan 20 and plates B. A cover plate 33'e`xtends over theoutside vwall opening 3|. A feed pipe 34 leads into the left hand or'front end of the pan 20 from the feed cup 35. The water supply, ifpreviously controlled, as from a remote control source such as a Watervfeed regulator located in the space to be heated, may beled into thefeed cup 35 through the line 36j on the other hand, if the water feed isto be by way of a dib rect control instrument such as indicated at 38.the water feed line 'may be located as indicated at 3l. A water leveleii'ualiz'er cup 39 has an air tube 40 which passes through the coverplate 33 and connects the cup 39 with the 'air pressure in the interiorof the furnace. The overflow pipe 4| leads lto a drain from theequalizer cup 39..

Referring now to Figs. 12 and 13, my invention also includes means forrapidly increasing the rate of evaporation in proportion to the rate`Aof introduction of water to the pan 2D. 'In Fig. `12, the .right handend of the pan 20 is eleva'teddby means of shortening the support rod28. In Fig. 13, the supporting 4rack 2| is elevated by means of the lug42 placed between thebottom of the rack 2| and the bottom of the pan 2|)inthe right hand conditions of demand and operation. By means of varyingthe distance of the bottoms of the plates B with respect to thewaterlevel range; or in other words, by Varying the depthof i'mmersionof the plates, a greatly increased evaporating rate is obtainable inproportionvto the rate of water supply or rate of elevation of the waterlevel. This result is explainable by the factv that there is asubstantial difference inthe rat of evaporation by an individual platebetween depth of immersion corresponding to a substantial amount ofwater immersion of the bottom of the plate and to a mere minimum wettingof the bottom of the plate respectively. In other words, when the waterlevel substantially coincides with the bottom of the plate, theevaporating rate of the latter is greatly reduced as compared to itsevaporating rate when the water level is higher. As shown in theaccompanying drawings, the bottom of the highest plate substantiallycoincides with the lowest water level, so that such highest plate willat all times receive some wetting action and will thereby not becomecompletely dry. I have found that this relative positioning of theheight of the highest plate with respect to the lowest water level is ofadvantage, since when the datesarepermitted te become alternately wetand dry, there exists a tendency lfor the ereationof increased limedeposits in the plates. The tilting oi the pan such as shown in Fig. 12,efr the tilting.

of water, and an upper portion `extending upwardly and outwardlytherefrom, th'e outer. terminal edge of said last-named portion yhavinga contour 'conforming substantially to the line oi advance of water ofabsorption from said body, said plate being of decreasingcross-sectional thickness from its water contacting portion to saidterminal edge.

An evaporating plate composed of a porous material adapted to absorbwater, comprising an intermediate lower portion adapted to be inser'tedin a body of water and upper and lateral portions extending upwardlyfrom and to both sides of said intermediate portion, the outer terminaledge of said upper and lateral portions having a contour conformingsubstantially to the line of advance of water of absorption from` saidbody of water, said plate being of decreasing Grossa-sectional thicknessfrom its water contacting portion to said terminal edge.

3. A vapor diffusing plate formed of capillary material, and rigid andself-supporting, and comprising a lower portion to be positioned in abody of water and an upper portion to be positioned above the water, andhaving at least part of said upper portion of less thickness than atleast part of 'said lower portion, and th'e margin of said upper portionremote from the body'of waterhaving such contour that water progressingfrom the body of water will reach all points of said marginsubstantially simultaneously.

4. In a vaporizing device comprising a recepta- `ele adapted to containwater and having a pair of spaced sides, and a body of water withinsaidreceptacle having its surface not above a predetermined levelappreciably below the upper edges 'of said sides: a vapor diffusingplate, formed of capillary material, positioned transversely of saidsides, and vcomprising a lower portion positioned inr the Water, anupper portion extending upwardly from said lower portion a substantialdistance above the upper edges of said sides, said upper portionincluding oppositely extending lateral portions extending a substantialdistance laterally of said sides respectively, and including dependingportions extending downwardly from said lateral portions respectivelyyexteriorly of said sides and vterminating not lower than saidpredetermined level, thereby to provide additional vapor diffusing areawithin the non-Siphoning limits of extent.

5. In a vaporizing device comprising a receptacle adapted to containwater and having a pair of spaced sides, and a body of water within saidreceptacle having its surface not above a predetermined levelappreciably below the upper edges of said sides: a vapor diiusing plate,formed of capillary material, positioned transversely of said sides, andcomprising a lower portion positioned in the water, an upper 'portionextending upward- 1y from said lower portion a substantial distanceabove the upper edges of said sides, said upper ally of said sidesrespectively, and including-depending portions extending downwardly Vfrom said lateral portions respectively exteriorlyr of said sides andterminating not lower than said predetermined level, thereby to provideadditional va- I por diffusing area within the non-siphoning limits ofextent, and the margin of said upper portion remote from the body ofwater having such contour that water progressingV from the body of waterwill reachrall points of said margin, substantially simultaneously.

` above the upper edges of said sides, said upper portion includingoppositely extending lateral portions extending a substantial distancelaterally of said sides respectively, and including depending portionsextending downwardly from said body of water will reach all points ofsaid margin substantially simultaneously. Y

9. A vapor diffusing plate, formed of capillary material, and comprisinga lower portion to be positioned in a body of water, and an upperportion to be positioned above the water, said upper portion extendingupwardly and laterallyv with respect to said lower` portion to an outerterminal margin remote from the body of water and being lateral portionsrespectively exteriorly of said sides and terminating not lower thansaid predetermined level, thereby to provide ladditional vapor diffusingarea within the non-Siphoning Ythe upward extent and lateral extent ofsaid upper portion being such and the contour of said margin being suchthat water progressing `from the body vof water will reach all points ofsaid margin substantially simultaneously.

8. A vapor diffusing plate, formed of capillary material, and,comprising a lower portion tovbe positioned in a body of water, and anupper portion to be positioned above the water, said upper portionextending upwardly and laterally to both sides with 'respect to saidlower portion to an outer terminal margin remote from the body of water,said margin extending Yfrom points up-l Wardly remotest to pointslaterally remotest from the respective sides of -said lower portion, theupward 'extent and lateral extents of said upper portion being such andthe contour of Ysaid margin being such that water progressing from theprogressively thinner at successive lines of front ofwater advance, saidmargin extending from points upwardly remotest to points laterallyremotest from sai-d lower portion, the upward extent and lateral extentof said upper portion being such and the contour of said margin beingsuch that water progressing from the body of water will reach al1 pointsof said margin substantially simultaneously.

10. A vapor diffusing plate, formed of capillary material, andcomprising a lower portion to be positioned in a body of water, and anupper portion to be positioned above the water, said upper portionextending upwardly and laterally to both sides with respect to saidlower portion to an outer terminal margin remote from the body of waterand being progressively thinner at successive lines of front of wateradvance, said margin extending from points upwardly remotest to pointslaterally remotest from said lower portion, the upward extent andlateral extent of said upper portion being such and the contour of saidmargin being such that water progressing from the body of water willreach all points of said margin substantially simultaneously. Y

11. In a vaporizing device comprising a receptacle adapted to containwater and having a pair vof spaced sides, and a body of water withinsaid receptacle having its surface not above a predetermined levelappreciably below the upper edges `of said sides: a vapor diffusingplate, formed of capillary material, positioned transversely of saidsides, and comprising a lower portion positioned in the water, an upperportion extending upward ly from said lower portion a substantialdistance above the kupper edges of said sides, said upper portionincluding lateral portions extending a substantial distance laterally ofsaid sides, and including depending portions extending downwardly fromsaid lateral'portions respectively exterior-y ly of said sides andterminating not lower than said predetermined level, thereby to provideadditional vapor diffusing area within the non-Siphoning limits ofextent, said upper portion being progressively thinner at successivelines of front of water advance, and the margin of said upper portionremote from the body of water having such contour that water progressingfrom the body of water will reach all pointsy of said marginsubstantially simultaneously.

OTTO J. KUENHOLD, SR.

